Keywords: composting, biosolids, sludge, pulp and paper mills, metals, nutrients, carbon to nitrogen ratio, growth study, biostabilisation, Canada, potting media, seedling growth, waste management
Potential utilisation of pulp and paper mill biosolids in composting and plant production: a case study at St. Marys Papers Ltd. (Canada)
The use of St Marys Paper biosolids as a soil additive or growth cover was investigated. Biosolids were mixed with a commercial potting media in five vol/vol ratios and employed in a greenhouse study. The biosolids were found to improve Pinus banksiana seedling growth, a 50% biosolids:50% ProMix mixture yielding the tallest plants and highest dry mass. To further biologically stabilise the biosolids, in–vessel composting studies were undertaken. Results indicated that a 3 parts biosolids:1 part wood chips:1 part sawdust mixture and initial C : N ratio of 30 sustained thermophilic conditions for 12 days reaching a maximum temperature of 52°C and final C : N ratio of 21.